Woah... that's a big job. Firstly, you'd have to downgrade the initial auth the packet that contains the password. You'd remove packet 1059 or whatever that littlle packet is that sends the Random key used in RC5 from patch 5180. We'll have to change the password cipher. Then, you'd have to edit packet 1055. With the auth server done... you would start by removing Exchange and Blowfish in the game server and replacing it with the NetDragon Authentication Cipher (the auth cipher). After receiving the first packet (1052), you'd generate the keys for the cipher (which is why the auth cipher has that method). Then, to continue to Set Location, you'd have to edit Character Info. After that, change the offsets for Set Location and you SHOULD log in.